Chiesi Farmaceutici is developing an inhaled formulation of the antiasthmatic corticosteroid budesonide [S 1320] that does not contain chlorofluorocarbons (CFCs).1 The formulation [budesonide Modulite™] is a hydrofluoroalkane (HFA)-propelled aerosol that is based on Chiesi’s proprietary Modulite™ technology. Chiesi has stated that the Modulite™ HFA technology has overcome the formulation problems associated with HFA propellants by making possible the development of flexible formulations that are able to modulate the median mass aerodynamic diameter of particles.